Wireline corer deployment and automatic alarm structure and method of use

Abstract

This invention relates to an automatic alarm structure for a wireline coring tool when it is deployed and its usage method. The structure includes an outer drill pipe, coiled tubing, a center rod, and an automatic alarm device. The automatic alarm device includes a slider, a spring catch, a radial spring, and a switch button. The coiled tubing is connected to the center rod via the slider, which slides against the inner wall of the outer drill pipe. The spring catch is installed in a radial groove on the outer wall of the slider, and the radial spring is installed between the spring catch and the slider. The switch button is radially mounted on the spring catch. The inner wall of the outer drill pipe has an annular spring catch groove that matches the spring catch. When the spring catch moves with the slider to the annular spring catch groove, its outer end is radially ejected into the groove under the action of the radial spring. The switch button moves radially synchronously with the spring catch, thus pressing the switch button. This invention helps ground personnel effectively and accurately determine whether the coring tool has been deployed to the target position, thereby guiding drilling and coring operations, ensuring effective core extraction, and improving operational efficiency.

Description

Technical Field

[0001] This invention relates to the field of pressure-holding coring technology, and in particular to an automatic alarm structure for a rope-type coring device when it is deployed and its usage method. Background Technology

[0002] A pressure-holding core sampler is a borehole sampler used to collect sediment core samples maintained at in-situ pressure for studying natural gas hydrates and other materials.

[0003] In the actual field coring process using a wireline-driven pressure-maintaining gas coring system, the center rod of the coring system needs to be connected using coiled tubing. This allows the coring system to be lowered down along the inner wall of the outer drill pipe to the target location, where coring operations can then begin. However, if coring begins before the coring system is lowered to the target location, problems such as the inability to collect rock cores and missed drilling strokes will occur.

[0004] Currently, the main way to determine whether the target position has been reached is by the sound after the well is in place or by the flow of drilling fluid. However, this method of determining whether the target position has been reached is inaccurate and can easily lead to core sampling failure. Summary of the Invention

[0005] To address the problem that during the process of using ropes to deploy a pressure-maintaining and gas-maintaining coring device downhole, it is impossible to accurately determine whether the coring device has been deployed to the target position, thus making it impossible to accurately determine whether drilling and coring can begin, this application proposes an automatic alarm structure for the deployment of a rope-mounted coring device and its usage method. This structure can accurately determine whether the coring device has been deployed to the target position, which is beneficial for guiding drilling and coring operations.

[0006] This application is achieved through the following technical solution:

[0007] The automatic alarm structure for the placement of the wireline coring device provided in this application includes an outer drill pipe, a coiled tubing, a center rod, and an automatic alarm device. The automatic alarm device includes a slider, a spring clip, a radial spring, and a switch button. The slider is installed inside the outer drill pipe and slides in cooperation with the inner wall of the outer drill pipe. The center rod is placed inside the outer drill pipe. The lower end of the coiled tubing is connected to the upper end of the slider, and the upper end of the center rod is connected to the lower end of the slider.

[0008] The outer wall of the slider has a radial groove for accommodating the spring clip. The spring clip is installed in the radial groove, and a radial spring is installed between the spring clip and the slider. Under the action of the radial spring, the spring clip tends to move radially so that the outer end of the spring clip protrudes outward from the outer surface of the slider.

[0009] The switch button is radially mounted on the spring clip. The inner wall of the outer drill rod has an annular spring clip groove that matches the spring clip. When the spring clip moves with the slider to the position of the annular spring clip groove, the outer end of the spring clip is radially ejected into the annular spring clip groove under the action of the radial spring. When the spring clip is ejected, it drives the switch button to move radially synchronously, so that the switch button is squeezed and pressed, thereby triggering the switch button. The switch button is connected to a cable.

[0010] Optionally, the slider has an outer circular surface adapted to the inner wall of the outer drill rod, and a radial groove is opened on the outer circular surface; the side of the spring clip has a boss, which can be inserted into the annular spring clip groove; the button of the switch button is located on the same side of the spring clip as the boss, and the button protrudes from the outer surface of the spring clip but does not exceed the boss; the upper side of the side of the boss has a guide slope adapted to the annular spring clip groove.

[0011] Optionally, the spring clip is radially inserted into the radial groove and then limited by upper and lower baffles, which are fixed to the slider; the boss passes through the space between the upper and lower baffles.

[0012] Optionally, a first spring hole is provided on the spring clip, and a second spring hole is provided on the groove wall of the radial groove of the slider at the position corresponding to the first spring hole, and the radial spring is installed in the first spring hole and the second spring hole.

[0013] Optionally, the spring clip has a radial hole for installing a switch button, and the slider has a wiring hole for routing wires. The wiring hole passes through the top surface of the slider and is connected to the radial groove through a side hole. The side hole and the radial hole are directly opposite each other. After the cable passes through the wiring hole and the side hole, it is electrically connected to the switch button in the radial hole.

[0014] Specifically, the lower end of the cable has a waterproof connector, which is installed in the side hole and the radial hole, and the waterproof connector is threaded into the radial hole.

[0015] Optionally, the switch button includes a body, a button, a first electrode, a second electrode, and a conductive sheet; the body is installed in the radial hole of the spring clip, the body has a cavity adapted to the button, a part of the button is installed in the cavity, and the other part of the button protrudes from the outer surface of the body, the inner ends of the first electrode and the second electrode extend into the cavity, and the outer ends of the first electrode and the second electrode are connected to the wires in the cable; one end of the conductive sheet is connected to the inner end of the first electrode by a torsion spring, and under the action of the torsion spring, the conductive sheet does not contact the second electrode; when an external force presses the button inward, the button can cause the conductive sheet to overcome the torsion spring force and rotate, thereby contacting the inner end of the second electrode, thus connecting the first electrode and the second electrode.

[0016] Specifically, the button is T-shaped, with its large end inside the cavity and its small end extending outside the cavity.

[0017] Optionally, the body is threadedly connected to a radial hole.

[0018] The method of using the automatic alarm structure for the placement of the rope-type core extractor provided in this application includes the following steps:

[0019] The coiled tubing is lowered, thereby lowering the center rod inside the outer drill pipe. During this process, the spring clip remains in contact with the inner wall of the outer drill pipe under the action of the radial spring, and the switch button is not pressed.

[0020] When the center rod reaches the target position, the spring clip aligns with the annular spring clip groove on the inner wall of the outer drill rod, and the spring clip is ejected into the annular spring clip groove of the outer drill rod under the elastic force of the radial spring.

[0021] At this time, the switch button moves radially synchronously under the action of the spring clip. The off button is pressed down, thereby triggering the switch button. The connected electrical signal is transmitted to the ground through the wires inside the cable. The change of the electrical signal can be observed on the ground to determine that the core sampler has been deployed to the target position, guiding the next step of drilling and core sampling.

[0022] Compared with the prior art, this application has the following beneficial effects:

[0023] 1. This application can help ground personnel to effectively and accurately determine whether the core sampler has been deployed to the target location, thereby guiding the drilling and core sampling operation, helping to ensure that the core sampler effectively obtains rock cores, and improving the efficiency of the operation;

[0024] 2. The special structural design of the switch button makes the switch button itself waterproof;

[0025] 3. This application adds a waterproof connector to prevent the drilling fluid from affecting the downhole power supply. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of the embodiments of this application and form part of this application, do not constitute a limitation on the embodiments of the present invention.

[0027] Figure 1 This is a schematic diagram of the automatic alarm structure for the cable-type core extractor being deployed into position when the central rod descends in the embodiment;

[0028] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0029] Figure 3 This is a schematic diagram of the automatic alarm structure for the rope-type core extractor being deployed when the central rod is lowered into position in the embodiment;

[0030] Figure 4 yes Figure 3 A magnified view of a section at point B in the middle;

[0031] Figure 5 This is a cross-sectional view of the slider in the embodiment;

[0032] Figure 6 This is a top view of the slider in the embodiment;

[0033] Figure 7 This is a side view of the slider in the embodiment;

[0034] Figure 8 This is a cross-sectional view of the ejector in the embodiment;

[0035] Figure 9 This is a top view of the ejector in the embodiment;

[0036] Figure 10 This is a side view of the ejector in the embodiment;

[0037] Figure 11 This is a schematic diagram of the structure when the switch button is not pressed in the embodiment;

[0038] Figure 12 This is a schematic diagram of the structure when the switch button is pressed in the embodiment;

[0039] Figure 13 This is a cross-sectional view of the baffle in the embodiment;

[0040] Figure 14 This is a top view of the baffle in the embodiment;

[0041] Figure 15 This is a side view of the baffle in the embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. It should also be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this invention is usually placed in during use, or the orientation or positional relationship that is commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0047] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] like Figure 1 , Figure 3 As shown, the automatic alarm structure for the placement of the wireline coring device disclosed in this embodiment includes an outer drill rod 1, a continuous tubing 2, a center rod 3, an automatic alarm device 4, and a cable 5. The center rod 3 is placed inside the outer drill rod 1.

[0049] like Figure 2 , Figure 4 As shown, the automatic alarm device 4 includes a slider 41, a spring clip 42, a radial spring 43, and a switch button 44. The lower end of the continuous tubing 2 is connected to the upper end of the slider 41, and the upper end of the center rod 3 is connected to the lower end of the slider 41. The slider 41 slides against the inner wall of the outer drill rod 1.

[0050] like Figures 5-7 As shown, the slider 41 has an outer circular surface 411 that is adapted to the inner wall of the outer drill rod 1. A radial groove 412 for accommodating the spring clip 42 is opened on the outer circular surface 411. The spring clip 42 is installed in the radial groove 412. A radial spring 43 is installed between the spring clip 42 and the slider 41. Under the action of the radial spring 43, the spring clip 42 has a tendency to move radially so that the outer end of the spring clip 42 protrudes outward from the outer circular surface 411.

[0051] The switch button 44 is radially mounted on the spring clip 42. The inner wall of the outer drill rod 1 has an annular spring clip groove 11 that matches the spring clip 42. When the spring clip 42 moves downward with the slider 41 to the position of the annular spring clip groove 11, the spring clip 42 enters the annular spring clip groove 11 radially under the action of the radial spring 43. When the spring clip 42 pops out, it drives the switch button 44 to move radially in sync, thereby pressing the switch button 44 and triggering the switch button 44.

[0052] In one possible design, the upper end of the slider 41 has a first journal 46, and the lower end of the slider 41 has a second journal 47. The first journal 46 is provided with an external thread to be threadedly connected to the continuous oil pipe 2, and the second journal 47 is provided with an internal thread hole to be threadedly connected to the center rod 3.

[0053] Specifically, a central through hole is provided in the center of the slider 41, which can be used as a wiring hole 413.

[0054] In one possible design, such as Figures 8-10 As shown, the side of the spring clip 42 has a protrusion 421, which can be inserted into the annular spring clip groove 11. The button 442 of the switch button 44 is located on the same side of the spring clip 42 as the protrusion 421. The button 442 protrudes from the outer surface of the spring clip 42 but does not extend beyond the protrusion 421.

[0055] In one possible design, the upper side of the boss 421 has a guide slope 424 that matches the annular spring groove 11, so that the spring 42 can be disengaged from the annular spring groove 11 under the action of an axial upward external force, thereby unlocking.

[0056] In one possible design, a first spring hole 423 is provided on the spring clip 42, and a second spring hole 415 is provided on the groove wall of the radial groove 412 of the slider 41 at a position corresponding to the first spring hole 423. The radial spring 43 is installed in the first spring hole 423 and the second spring hole 415. The natural length of the radial spring 43 is greater than the sum of the depths of the first spring hole 423 and the second spring hole 415.

[0057] For ease of assembly, in one possible design, the spring clip 42 is radially inserted into the radial groove 412 and then limited by upper and lower baffles 45. The upper and lower baffles 45 are fixed to the slider 41 by countersunk screws 7. The boss 421 passes between the upper and lower baffles 45. The slider 41 has screw holes 416 that fit the countersunk screws 7, and the baffles 45 have countersunk holes 451 that fit the countersunk screws 7. In particular, such as Figures 13-15 As shown, the outer surfaces of the upper and lower baffles 45 are cylindrical surfaces that match the outer circular surface 411 of the slider 41, and the outer surfaces of the upper and lower baffles 45 are flush with the outer circular surface 411.

[0058] Notably, the 42-piece cartridge is rectangular.

[0059] In one possible design, the spring clip 42 has a radial hole 422 for mounting a switch button 44, and the slider 41 has a wiring hole 413 for wiring. The wiring hole 413 passes through the top surface of the slider 41 and communicates with the inside of the continuous oil pipe 2. The wiring hole 413 communicates with the radial groove 412 through the side hole 414. The side hole 414 is directly opposite the radial hole 422. The cable 5 passes through the continuous oil pipe 2, the wiring hole 413, and the side hole 414 and is electrically connected to the switch button 44 in the radial hole 422.

[0060] In one possible design, such as Figure 11 , Figure 12 As shown, the switch button 44 includes a body 441, a button 442, a first electrode 445, a second electrode 446, and a conductive sheet 447. The body 441 has a cavity 443 adapted to the button 442. A part of the button 442 is installed in the cavity 443, and the other part of the button 442 protrudes from the outer surface of the body 441. The inner ends of the first electrode 445 and the second electrode 446 extend into the cavity 443, and the outer ends of the first electrode 445 and the second electrode 446 are exposed on the outer surface of the body 441 and are respectively connected to wires 448, which are installed inside the cable 5. One end of the conductive sheet 447 is connected to the inner end of the first electrode 445 by a torsion spring. Under normal circumstances, under the action of the torsion spring, the conductive sheet 447 does not contact the second electrode 446; if Figure 12 As shown, when an external force is applied, pressing button 442 inward causes the conductive sheet 447 to rotate against the torsion spring force and then contact the inner end of the second electrode 446, thereby connecting the first electrode 445 and the second electrode 446.

[0061] Specifically, button 442 is T-shaped, with its large end installed inside cavity 443 and its small end extending outside cavity 443.

[0062] In one possible design, the outer wall of the main body 441 is provided with external threads, and the main body 441 is threadedly connected to the radial hole 422 of the spring clip 42.

[0063] It is worth noting that the switch button 44 is a self-resetting spring button. As long as no force is applied to it, it will automatically spring back and the switch will be turned off. For example, a reset spring can be installed between the button 442 and the cavity wall of the cavity 443. This is a conventional technique in the field and will not be described in detail here.

[0064] To prevent liquid from entering the switch button 44, in one possible design, the lower end of the cable 5 has a waterproof connector 6. The waterproof connector 6 is installed in the side hole 414 and the radial hole 422, and is threadedly connected to the radial hole 422, so that the waterproof connector 6 and the spring clip 42 are connected as a whole. In particular, the waterproof connector 6 is a stainless steel waterproof connector. The waterproof connector 6 can prevent drilling fluid from affecting the downhole power supply.

[0065] The method for using the automatic alarm structure of the rope-type core extractor in place includes the following steps:

[0066] S1, the continuous tubing 2 is continuously lowered by the working equipment, thereby lowering the center rod 3 inside the outer drill pipe 1. During this process, the spring clip 42 is kept in contact with the inner wall of the outer drill pipe 1 under the action of the radial spring 43, and the switch button 44 is not pressed.

[0067] S2, when the center rod 3 reaches the target position and the outer drill rod 1 is in the corresponding position, the boss 421 on the spring clip 42 corresponds to the position of the annular spring clip groove 11 on the inner wall of the outer drill rod 1, and the spring clip 42 is ejected into the annular spring clip groove 11 of the outer drill rod 1 under the elastic force of the radial spring 43.

[0068] At this time, the switch button 44 moves radially synchronously under the action of the spring clip 42, and then comes into contact with the baffle 45. The button 442 is pushed radially, which presses the conductive sheet 447 radially, thereby connecting the first electrode 445 and the second electrode 446. The connected electrical signal is transmitted to the ground through the wire 448 inside the cable 5. Therefore, the change of electrical signal can be observed on the ground to determine that the core sampler has been deployed to the target position, guiding the next step of drilling and core sampling.

[0069] S3, when the core drilling is completed, the coiled tubing 2 is lifted by the working equipment. At this time, the boss 421 is pressed into the slider 41 by the resistance of the radial spring 43 under the action of the guide inclined surface 424, and the unlocking is completed, thereby realizing the upward lifting of the center rod 3 inside the outer drill rod 1.

[0070] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An automatic alarm structure for the placement of a rope-type core extractor, characterized in that: It includes an external drill pipe (1), a coiled tubing (2), a center rod (3), and an automatic alarm device (4). The automatic alarm device (4) includes a slider (41), a spring clip (42), a radial spring (43), and a switch button (44). The slider (41) is installed inside the external drill pipe (1) and slides in cooperation with the inner wall of the external drill pipe (1). The center rod (3) is placed inside the external drill pipe (1). The lower end of the coiled tubing (2) is connected to the upper end of the slider (41), and the upper end of the center rod (3) is connected to the lower end of the slider (41). The outer wall of the slider (41) has a radial groove (412) for accommodating the spring clip (42). The spring clip (42) is installed in the radial groove (412). A radial spring (43) is installed between the spring clip (42) and the slider (41). Under the action of the radial spring (43), the spring clip (42) tends to move radially so that the outer end of the spring clip (42) protrudes outward from the outer surface of the slider (41). The switch button (44) is radially mounted on the spring clip (42). The inner wall of the outer drill rod (1) has an annular spring clip groove (11) that matches the spring clip (42). When the spring clip (42) moves to the position of the annular spring clip groove (11) with the slider (41), the outer end of the spring clip (42) is radially ejected into the annular spring clip groove (11) under the action of the radial spring (43). When the spring clip (42) is ejected, it drives the switch button (44) to move radially synchronously, so that the switch button (44) is squeezed and pressed, thereby triggering the switch button (44). The switch button (44) is connected to the cable (5). The switch button (44) includes a body (441), a button (442), a first electrode (445), a second electrode (446), and a conductive sheet (447). The side of the spring clip (42) has a protrusion (421), which can be inserted into the annular spring clip groove (11). The button (442) of the switch button (44) is located on the same side of the spring clip (42) as the protrusion (421). The button (442) protrudes from the outer surface of the spring clip (42) but does not extend beyond the protrusion (421). The spring clip (42) is radially inserted into the radial groove (412) and limited by the baffle (45), and the baffle (45) is fixedly connected to the slider (41); The switch button (44) can move radially synchronously under the action of the spring clip (42) and come into contact with the baffle (45). The button (442) can be radially pushed by the baffle (45) and radially press the conductive sheet (447). The conductive sheet (447) that is radially pressed by the button (442) can connect the first electrode (445) and the second electrode (446).

2. The automatic alarm structure for the placement of the rope-type core extractor according to claim 1, characterized in that: The slider (41) has an outer circular surface (411) that is adapted to the inner wall of the outer drill rod (1), and a radial groove (412) is opened on the outer circular surface (411); The upper side of the boss (421) has a guide slope (424) that is adapted to the annular spring groove (11).

3. The automatic alarm structure for the placement of the rope-type core extractor according to claim 2, characterized in that: The spring clip (42) is radially inserted into the radial groove (412) and then limited by the upper and lower baffles (45). The upper and lower baffles (45) are fixedly connected to the slider (41). The boss (421) passes between the upper and lower baffles (45).

4. The automatic alarm structure for the placement of the rope-type core extractor according to claim 1, characterized in that: A first spring hole (423) is provided on the spring clip (42), and a second spring hole (415) is provided on the groove wall of the radial groove (412) of the slider (41) at the position corresponding to the first spring hole (423). The radial spring (43) is installed in the first spring hole (423) and the second spring hole (415).

5. The automatic alarm structure for the placement of the rope-type core extractor according to claim 1, characterized in that: The spring clip (42) has a radial hole (422) for installing a switch button (44), and the slider (41) has a wiring hole (413) for wiring. The wiring hole (413) passes through the top surface of the slider (41), and the wiring hole (413) passes through the side hole (414) and the radial groove (412). The side hole (414) is directly opposite to the radial hole (422). The cable (5) passes through the wiring hole (413) and the side hole (414) and is electrically connected to the switch button (44) in the radial hole (422).

6. The automatic alarm structure for the placement of the rope-type core extractor according to claim 5, characterized in that: The lower end of the cable (5) has a waterproof connector (6), which is installed in the side hole (414) and the radial hole (422). The waterproof connector (6) is threadedly connected to the radial hole (422).

7. The automatic alarm structure for the rope-type core extractor in place according to any one of claims 1-6, characterized in that: The main body (441) is installed in the radial hole (422) of the spring clip (42). The main body (441) has a cavity (443) adapted to the button (442). A part of the button (442) is installed in the cavity (443), and another part of the button (442) protrudes from the outer surface of the main body (441). The inner ends of the first electrode (445) and the second electrode (446) extend into the cavity (443), and the outer ends of the first electrode (445) and the second electrode (446) are connected to the wire (448) in the cable (5). One end of the conductive sheet (447) is connected to the inner end of the first electrode (445) by a torsion spring. Under the action of the torsion spring, the conductive sheet (447) does not contact the second electrode (446). When an external force presses the button (442) inward, the button (442) can cause the conductive sheet (447) to rotate against the torsion spring force and then contact the inner end of the second electrode (446), thereby connecting the first electrode (445) and the second electrode (446).

8. The automatic alarm structure for the placement of the rope-type core extractor according to claim 7, characterized in that: The button (442) is T-shaped, with its large end installed inside the cavity (443) and its small end extending outside the cavity (443).

9. The automatic alarm structure for the placement of the rope-type core extractor according to claim 7, characterized in that: The main body (441) is threadedly connected to the radial hole (422).

10. The method of using the automatic alarm structure for the placement of the rope-type core extractor as described in any one of claims 1-9, characterized in that: Includes the following steps: The coiled tubing (2) is lowered, thereby lowering the center rod (3) inside the outer drill pipe (1). During this process, the spring clip (42) remains in contact with the inner wall of the outer drill pipe (1) under the action of the radial spring (43), and the switch button (44) is not pressed. When the center rod (3) reaches the target position, the spring clip (42) corresponds to the position of the annular spring clip groove (11) on the inner wall of the outer drill rod (1), and the spring clip (42) is ejected into the annular spring clip groove (11) of the outer drill rod (1) under the elastic force of the radial spring (43). At this time, the switch button (44) moves radially synchronously under the action of the spring clip (42), and the switch button (44) is pressed down, thereby triggering the switch button (44). The connected electrical signal is transmitted to the ground through the wire (448) inside the cable (5). The change of the electrical signal can be observed on the ground to determine that the core sampler has been deployed to the target position, guiding the next drilling and core sampling operation.

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